1. Field of the Invention
The present invention relates to an air-conditioning system.
2. Related Background Art
Asymmetric membranes formed of various polymeric materials have been conventionally known. Examples of such asymmetric membranes include membranes using fluorine-containing polyimides as coating materials (Patent Documents 1 and 2), a membrane using a polyacrylonitrile (Patent Document 3), a membrane using a polyolefin (Patent Document 4), a membrane using a polyethersulfone (Patent Document 5), membranes using poly(1-trimethylsilyl-1-propyne) (PTMSP) (Patent Documents 6 and 7), and membranes manufactured by sol-gel method. All of these membranes are intended for gas separation or liquid-liquid separation, and their gas permeability is not sufficient.
The recent technological advances have made it possible to increase air-tightness even in spaces such as automobiles, where increasing the air-tightness has been difficult. When many passengers are aboard an automobile with such high air-tightness for long hours, a decrease in oxygen concentration or an increase in carbon dioxide concentration will occur, which may cause the passengers a headache or an unpleasant feel. Thus, the introduction of an adequate amount of outside air is necessary.
However, urban roads, highways, and the like are contaminated with pollutants such as dust; therefore, direct introduction of outside air into automobiles has been a big problem in view of the passengers' health. One example of a method for solving this problem is a method in which an inlet for introducing outside air is provided with a filter for removing pollutants in the air such as suspended matter.
Non-woven cloths, mechanical filters, and the like have been conventionally used as such filters. In Patent Document 10, an air-conditioning system for the entire automobile is suggested.    Patent Document 1: JP 05-7749 A    Patent Document 2: JP 06-188167 A    Patent Document 3: JP 05-184891 A    Patent Document 4: JP 2002-535115 A    Patent Document 5: JP 09-285723 A    Patent Document 6: JP60-132605 A    Patent Document 7: JP 02-222715 A    Patent Document 8: JP 11-192420 A    Patent Document 9: JP 11-9976 A    Patent Document 10: JP 2004-203367 A